/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch licenses this file to you under
 * the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.elasticsearch.index.fielddata;

import org.apache.lucene.util.Bits;
import org.apache.lucene.util.Bits.MatchAllBits;

/**
 * Exposes multi-valued view over a single-valued instance.
 * <p>
 * This can be used if you want to have one multi-valued implementation
 * that works for single or multi-valued types.
 */
final class SingletonSortedNumericDoubleValues extends SortedNumericDoubleValues {
    private final NumericDoubleValues in;
    private final Bits docsWithField;
    private double value;
    private int count;

    public SingletonSortedNumericDoubleValues(NumericDoubleValues in, Bits docsWithField) {
        this.in = in;
        this.docsWithField = docsWithField instanceof MatchAllBits ? null : docsWithField;
    }

    /** Return the wrapped {@link NumericDoubleValues} */
    public NumericDoubleValues getNumericDoubleValues() {
        return in;
    }

    /** Return the wrapped {@link Bits} */
    public Bits getDocsWithField() {
        return docsWithField;
    }

    @Override
    public void setDocument(int doc) {
        value = in.get(doc);
        if (docsWithField != null && value == 0 && docsWithField.get(doc) == false) {
            count = 0;
        } else {
            count = 1;
        }
    }

    @Override
    public double valueAt(int index) {
        return value;
    }

    @Override
    public int count() {
        return count;
    }
}
